Problems with "assuming ownership" on main user profile

The main profile on my computer (running XP home) was set up with a password.
When my motherboard died I needed to retrieve certain documents by putting
the hard drive in an external case and assuming ownership of my password
protected user folder on another computer.

I've repaired the computer but (as anticipated) the system no longer
recognizes my main user profile (with all my applications and files). Should
the solution be to simply take ownership back from within safe mode? Perhaps
I should try again but this didn't seem to work when I tried the first time?

Looks like lots of great knowledge on here - hoping this is an easy fix.
Thanks in advance.